The Clubsport's 498bhp engine drives through a six-speed manual gearbox and a four-wheel-drive Quattro drivetrain like the one in other transverse-engined high-performance Audis, as well as Volkswagen 4Motion models. Audi claims a 0-62mph time of 3.7 seconds and 0-124mph in less than 11 seconds.

The A1's steel monocoque body has been lightened by 400kg in the Clubsport thanks to extensive use of carbonfibre.

Sielaff says this would be too extreme for mass production, not least because of cost, but reckons that a showroom car could be lightened by 200kg compared with an all-steel model.

The front wings, doors and rear side panels are 60mm wider than those of a standard A1, while the rear seats have been stripped out to make way for racing harnesses and two crash helmets, adorned with the names of Audi CEO Rupert Stadler and research and development chief Michael Dick.

The Worthersee festival is celebrating its 30th anniversary this year. It started as a gathering of Golf GTI enthusiasts eager to show off their tuned and body-kitted cars, but has now become an annual meeting point for Audi, Seat and Skoda enthusiasts as well as fans of all Volkswagens.